1. Technical Field
According to a first aspect, the invention relates to a method for manufacturing and reinforcing a corner in an object made from a sandwich structure, comprising a core layer, which is arranged between two cover layers, at least one of which is a plastic cover layer.
2. Description of the Related Art
A method for manufacturing an object from a thermoplastic sandwich structure comprising object parts which are at an angle is known in the art. European patent 431,669 for example discloses a method for manufacturing an object from a thermoplastic sandwich material, in which the normals of at least two surfaces or object parts are at an angle to one another. This known method comprises at least the steps of softening a part of one of the surfaces of the thermoplastic sandwich material over a distance which corresponds to at least the length of an imaginary folding line of the corner between the two surfaces with the aid of a die, in which the die is pressed at least partially into the top layer of the thermoplastic sandwich material, and folding the two surfaces of the thermoplastic material about the folding line in such a manner that the surface which has been softened comes to lie on the inside of the corner as a result. This method results in an object having two surfaces which are at an angle to one another, in which the excess material of the softened top layer of the sandwich material is present on the inside of the corner, and is melted into the foam of the core in the folded position. This prevents the excess material from bulging out and thus ensures that a satisfactory fold or corner can be obtained. A drawback of such objects known in the art is the low strength thereof at the location of the corner as a result of the folded fibre-reinforced top layer. In particular the impact strength on the outside of the corner and the stiffness and/or strength leave something to be desired.
Generally, with sandwich structures based on a thermosetting core layer with thermosetting cover layers, such as honeycomb panels, the cover layer and, if desired, the honeycomb at the location of the corner to be formed are removed, the honeycomb is filled with a potting compound and the remaining potting compound is removed after the bending operation, following which the unit is hardened. Such a filling operation not only results in a significant increase in weight (although such sandwich structures are in fact intended for lightweight applications), but also increases the (local) stiffness and strength only slightly. In addition, when sandwich structures are being joined to one another, aluminium extruded parts are often used and/or strips are milled off the sandwich panel locally, into which the head ends of a sandwich panel which is to be joined therewith are placed. The abovementioned joints result in a significant increase in weight or a considerable local reduction in strength and stiffness.
It is an object of the present invention to reduce the abovementioned drawbacks and/or to provide an alternative method.